Sometime in early 1987, Hornby were forced to pull out of the N Gauge Market largely due to the UK's financial problems of the time. It simply wasn't viable.

Minitrix were producing (in my opinion) some of the best N gauge models available at the time, and I remember the feeling of dismay at the prospect of having this supply cut off when Hornby made the announcement.
However, Minitrix - the German manufacturer - continued to distribute the UK models, and these started to appear in shops in plastic boxes with the green/yellow MiniTrix packaging, and for a while all of the UK models were available.

The Railfreight Grey model was one of two Class 47s introduced to the market after Hornby had ceased distribution in 1987. The other being the un-named Intercity model.